Field of the Invention
The present invention relates to a photovoltaic module, and more particularly, it relates to a photovoltaic module including a plurality of photovoltaic elements.
Description of the Background Art
A photovoltaic module in which a plurality of photovoltaic elements are serially connected with each other is known in general, as disclosed in Japanese Patent Laying-Open No 10-65192 (1998), for example.
Each photovoltaic element constituting the conventional photovoltaic module disclosed in the aforementioned Japanese Patent Laying-Open No 10-65192 includes a finger electrode consisting of a metallic wire for collecting generated currents, bonded to a element surface through a conductive adhesive, and a bus bar electrode consisting of foil or a metallic wire for aggregating currents collected by the finger electrode consisting of a metallic wire. The bus bar electrode of the conventional photovoltaic element is so bonded to a surface of a non-light emitting region other than a light emitting region of the photovoltaic element as to be electrically connected to the finger electrode.
In the photovoltaic module disclosed in the aforementioned Japanese Patent Laying-Open No 10-65192, the metallic wire is employed as the finger electrode, and hence the conductive adhesive for bonding the finger electrode and the element surface must be disadvantageously provided independently of the finger electrode.
On the other hand, a photovoltaic element in which a finger electrode and a bus bar electrode are formed of conductive paste has been proposed in general. In a case where a photovoltaic module is formed from the conventional photovoltaic elements, a tab electrode consisting of foil is bonded on the bus bar electrode formed of the conductive paste of the photovoltaic elements adjacent to each other by soldering, whereby the photovoltaic elements are serially connected with each other. In a case where this finger electrode formed of the conductive paste is employed, the conductive paste has an adhesion function, and hence an adhesive for bonding the finger electrode and the element surface is not required to be provided dissimilarly to a case where the finger electrode consisting of the metallic wire is employed.
In the aforementioned conventional photovoltaic module in which the finger electrode and the bus bar electrode are formed of the conductive paste and the tab electrode consisting of foil is formed on the bus bar electrode, however, in a case where an excessive tensile stress is applied to the bus bar electrode through the tab electrode, the bus bar electrode is likely to be separated from a surface of the photovoltaic element.